To improve their surface stability and performance, metallic interconnects (aka bipolar plates) in SOFC stacks are often fabricated with a cathode-side conductive oxide protection layer or coating. This electrically conductive oxide layer exhibits some degree of oxygen ion conduction, which allows some oxygen penetration through the protection layer, leading to oxide scale growth at the interface between the protection layer and metallic substrate. If the resulting scale/metal interface is structurally weak, spallation, peeling, or delamination can occur along the scale/metal interface. This can lead to degradation of interconnect performance and reduction of useful stack life. Scale adhesion can be improved by adding oxygen active elements to the alloy during alloy fabrication or by surface treatment of alloys with the oxygen active elements after alloy fabrication, but both of these approaches add cost. Furthermore, reactive element surface treatment may create an extra layer that can negatively affect the surface stability due to the difficulty to sintering protection layers onto the reactive oxide layer.
The present invention includes an assembly approach that includes integrating the protection layer (coating) fabrication and reactive element treatment into a single processing step. That eliminates or at least diminishes many of the problems associated with the prior art and provides new and novel advantages and features.
Additional advantages and novel features of the present invention will be set forth as follows and will be readily apparent from the descriptions and demonstrations set forth herein. Accordingly, the following descriptions of the present invention should be seen as illustrative of the invention and not as limiting in any way.